The present invention relates to the manufacture of tires, and more particularly, to the laying of threads to constitute a reinforcement of the tire, such as, for instance, a carcass.
In this field of art, methods and machines are already known which make it possible to include the manufacture of the tire reinforcements in the assembling of the components of tire. This means that, rather than having recourse to semifinished products, such as reinforcement plies, a reinforcement is made or reinforcements are made in situ from a single spool of thread at the time that the tire is manufactured. The solution described in U.S. Pat. No. 4,795,523 is, for instance, known. Although that solution constitutes a considerable advance over the conventional techniques employing reinforcement plies, it has the drawback that a machine designed to carry out that solution can only produce tires which always have the same number of threads in the reinforcement thus produced, for instance, always the same number of radial hoops in a radial carcass.
The solution described in U.S. Pat. No. 4,952,259 is also known. That proposal, which is based on projecting a thread in the manner of a whiplash, makes it possible to sweep across the ordinary angles of so-called crown plies. It also makes it possible to produce carcass reinforcements in which the thread extends from one bead to the other of the tire. However, in that device it is difficult to lay the threads at the small angles which are used at times in certain crown reinforcements. The angles are measured with respect to a reference defined by a plane perpendicular to the axis of rotation of the tire in accordance with the well-established convention.